Enable language preview option for fsi in the ide

src/fsharp/service/service.fs

@@ -742,7 +742,7 @@ type BackgroundCompiler(legacyReferenceResolver, projectCacheSize, keepAssemblyC
     member bc.ParseAndCheckProject(options, userOpName) =
         reactor.EnqueueAndAwaitOpAsync(userOpName, "ParseAndCheckProject", options.ProjectFileName, fun ctok -> bc.ParseAndCheckProjectImpl(options, ctok, userOpName))
 
-    member __.GetProjectOptionsFromScript(filename, sourceText, loadedTimeStamp, otherFlags, useFsiAuxLib: bool option, useSdkRefs: bool option, assumeDotNetFramework: bool option, extraProjectInfo: obj option, optionsStamp: int64 option, userOpName) = 
+    member __.GetProjectOptionsFromScript(filename, sourceText, previewEnabled, loadedTimeStamp, otherFlags, useFsiAuxLib: bool option, useSdkRefs: bool option, assumeDotNetFramework: bool option, extraProjectInfo: obj option, optionsStamp: int64 option, userOpName) = 
         reactor.EnqueueAndAwaitOpAsync (userOpName, "GetProjectOptionsFromScript", filename, fun ctok -> 
           cancellable {
             use errors = new ErrorScope()
@@ -751,10 +751,16 @@ type BackgroundCompiler(legacyReferenceResolver, projectCacheSize, keepAssemblyC
             let useFsiAuxLib = defaultArg useFsiAuxLib true
             let useSdkRefs =  defaultArg useSdkRefs true
             let reduceMemoryUsage = ReduceMemoryFlag.Yes
+            let previewEnabled = defaultArg previewEnabled false
 
             // Do we assume .NET Framework references for scripts?
             let assumeDotNetFramework = defaultArg assumeDotNetFramework true
-            let otherFlags = defaultArg otherFlags [| |]
+            let extraFlags =
+                if previewEnabled then
+                    [| "--langversion:preview" |]
+                else
+                    [||]
+            let otherFlags = defaultArg otherFlags extraFlags
             let useSimpleResolution = 
 #if ENABLE_MONO_SUPPORT
                 runningOnMono || otherFlags |> Array.exists (fun x -> x = "--simpleresolution")
@@ -1142,9 +1148,9 @@ type FSharpChecker(legacyReferenceResolver,
         backgroundCompiler.ParseAndCheckProject(options, userOpName)
 
     /// For a given script file, get the ProjectOptions implied by the #load closure
-    member __.GetProjectOptionsFromScript(filename, source, ?loadedTimeStamp, ?otherFlags, ?useFsiAuxLib, ?useSdkRefs, ?assumeDotNetFramework, ?extraProjectInfo: obj, ?optionsStamp: int64, ?userOpName: string) = 
+    member __.GetProjectOptionsFromScript(filename, source, ?previewEnabled, ?loadedTimeStamp, ?otherFlags, ?useFsiAuxLib, ?useSdkRefs, ?assumeDotNetFramework, ?extraProjectInfo: obj, ?optionsStamp: int64, ?userOpName: string) = 
         let userOpName = defaultArg userOpName "Unknown"
-        backgroundCompiler.GetProjectOptionsFromScript(filename, source, loadedTimeStamp, otherFlags, useFsiAuxLib, useSdkRefs, assumeDotNetFramework, extraProjectInfo, optionsStamp, userOpName)
+        backgroundCompiler.GetProjectOptionsFromScript(filename, source, previewEnabled, loadedTimeStamp, otherFlags, useFsiAuxLib, useSdkRefs, assumeDotNetFramework, extraProjectInfo, optionsStamp, userOpName)
 
     member __.GetProjectOptionsFromCommandLineArgs(projectFileName, argv, ?loadedTimeStamp, ?extraProjectInfo: obj) = 
         let loadedTimeStamp = defaultArg loadedTimeStamp DateTime.MaxValue // Not 'now', we don't want to force reloading

src/fsharp/service/service.fsi

@@ -228,7 +228,7 @@ type public FSharpChecker =
     /// so that an 'unload' and 'reload' action will cause the script to be considered as a new project,
     /// so that references are re-resolved.</param>
     /// <param name="userOpName">An optional string used for tracing compiler operations associated with this request.</param>
-    member GetProjectOptionsFromScript : filename: string * sourceText: ISourceText * ?loadedTimeStamp: DateTime * ?otherFlags: string[] * ?useFsiAuxLib: bool * ?useSdkRefs: bool * ?assumeDotNetFramework: bool * ?extraProjectInfo: obj * ?optionsStamp: int64 * ?userOpName: string -> Async<FSharpProjectOptions * FSharpErrorInfo list>
+    member GetProjectOptionsFromScript : filename: string * sourceText: ISourceText * ?previewEnabled:bool * ?loadedTimeStamp: DateTime * ?otherFlags: string[] * ?useFsiAuxLib: bool * ?useSdkRefs: bool * ?assumeDotNetFramework: bool * ?extraProjectInfo: obj * ?optionsStamp: int64 * ?userOpName: string -> Async<FSharpProjectOptions * FSharpErrorInfo list>
 
     /// <summary>
     /// <para>Get the FSharpProjectOptions implied by a set of command line arguments.</para>

vsintegration/src/FSharp.Editor/LanguageService/FSharpProjectOptionsManager.fs

@@ -20,6 +20,7 @@ open System.Threading
 open Microsoft.VisualStudio.Shell.Interop
 open Microsoft.VisualStudio.LanguageServices.Implementation.TaskList
 open Microsoft.CodeAnalysis.ExternalAccess.FSharp.LanguageServices
+open Microsoft.VisualStudio.FSharp.Interactive.Session
 
 [<AutoOpen>]
 module private FSharpProjectOptionsHelpers =
@@ -97,7 +98,7 @@ type private FSharpProjectOptionsReactor (_workspace: VisualStudioWorkspace, set
             match singleFileCache.TryGetValue(document.Id) with
             | false, _ ->
                 let! sourceText = document.GetTextAsync(ct) |> Async.AwaitTask
-                let! scriptProjectOptions, _ = checkerProvider.Checker.GetProjectOptionsFromScript(document.FilePath, sourceText.ToFSharpSourceText())
+                let! scriptProjectOptions, _ = checkerProvider.Checker.GetProjectOptionsFromScript(document.FilePath, sourceText.ToFSharpSourceText(), SessionsProperties.fsiPreview)
                 let projectOptions =
                     if isScriptFile document.FilePath then
                         scriptProjectOptions

vsintegration/src/FSharp.LanguageService/BackgroundRequests.fs

@@ -11,6 +11,7 @@ open Microsoft.VisualStudio.TextManager.Interop
 open Microsoft.VisualStudio.Text
 open FSharp.Compiler.SourceCodeServices
 open Microsoft.VisualStudio.FSharp.LanguageService.SiteProvider
+open Microsoft.VisualStudio.FSharp.Interactive.Session
 
 #nowarn "44" // use of obsolete CheckFileInProjectAllowingStaleCachedResults
 
@@ -94,7 +95,7 @@ type internal FSharpLanguageServiceBackgroundRequests_DEPRECATED
                         lazy // This portion is executed on the language service thread
                             let timestamp = if source=null then System.DateTime(2000,1,1) else source.OpenedTime // source is null in unit tests
                             let checker = getInteractiveChecker()
-                            let checkOptions, _diagnostics = checker.GetProjectOptionsFromScript(fileName,  FSharp.Compiler.Text.SourceText.ofString sourceText, timestamp, [| |]) |> Async.RunSynchronously
+                            let checkOptions, _diagnostics = checker.GetProjectOptionsFromScript(fileName,  FSharp.Compiler.Text.SourceText.ofString sourceText, SessionsProperties.fsiPreview, timestamp, [| |]) |> Async.RunSynchronously
                             let referencedProjectFileNames = [| |]
                             let projectSite = ProjectSitesAndFiles.CreateProjectSiteForScript(fileName, referencedProjectFileNames, checkOptions)
                             { ProjectSite = projectSite

vsintegration/src/FSharp.VS.FSI/Properties.resx

@@ -148,4 +148,14 @@
   <data name="FSharpInteractiveDebugging" xml:space="preserve">
     <value>Debugging</value>
   </data>
+  <data name="FSharpInteractivePreview" xml:space="preserve">
+    <value>FSI Preview</value>
+  </data>
+  <data name="FSharpInteractivePreviewModeDescr" xml:space="preserve">
+    <value>Enable preview of in-development language features in F# Interactive</value>
+  </data>
+  <data name="FSharpInteractivePreviewMode" xml:space="preserve">
+    <value>Enable preview language features</value>
+  </data>
+
 </root>

vsintegration/src/FSharp.VS.FSI/fsiLanguageService.fs

@@ -36,30 +36,35 @@ module internal ContentType =
 [<ClassInterface(ClassInterfaceType.AutoDual)>]
 [<Guid("4489e9de-6ac1-3cd6-bff8-a904fd0e82d4")>]
 type FsiPropertyPage() = 
-    inherit DialogPage()    
-       
+    inherit DialogPage()
+
     [<ResourceCategory(SRProperties.FSharpInteractiveMisc)>]
-    [<ResourceDisplayName(SRProperties.FSharpInteractive64Bit)>] 
-    [<ResourceDescription(SRProperties.FSharpInteractive64BitDescr)>] 
+    [<ResourceDisplayName(SRProperties.FSharpInteractive64Bit)>]
+    [<ResourceDescription(SRProperties.FSharpInteractive64BitDescr)>]
     member this.FsiPreferAnyCPUVersion with get() = SessionsProperties.useAnyCpuVersion and set (x:bool) = SessionsProperties.useAnyCpuVersion <- x
 
     [<ResourceCategory(SRProperties.FSharpInteractiveMisc)>]
     [<ResourceDisplayName(SRProperties.FSharpInteractiveOptions)>]
-    [<ResourceDescription(SRProperties.FSharpInteractiveOptionsDescr)>] 
+    [<ResourceDescription(SRProperties.FSharpInteractiveOptionsDescr)>]
     member this.FsiCommandLineArgs with get() = SessionsProperties.fsiArgs and set (x:string) = SessionsProperties.fsiArgs <- x
 
     [<ResourceCategory(SRProperties.FSharpInteractiveMisc)>]
     [<ResourceDisplayName(SRProperties.FSharpInteractiveShadowCopy)>]
-    [<ResourceDescription(SRProperties.FSharpInteractiveShadowCopyDescr)>] 
+    [<ResourceDescription(SRProperties.FSharpInteractiveShadowCopyDescr)>]
     member this.FsiShadowCopy with get() = SessionsProperties.fsiShadowCopy and set (x:bool) = SessionsProperties.fsiShadowCopy <- x
 
     [<ResourceCategory(SRProperties.FSharpInteractiveDebugging)>]
     [<ResourceDisplayName(SRProperties.FSharpInteractiveDebugMode)>]
-    [<ResourceDescription(SRProperties.FSharpInteractiveDebugModeDescr)>] 
+    [<ResourceDescription(SRProperties.FSharpInteractiveDebugModeDescr)>]
     member this.FsiDebugMode with get() = SessionsProperties.fsiDebugMode and set (x:bool) = SessionsProperties.fsiDebugMode <- x
 
+    [<ResourceCategory(SRProperties.FSharpInteractivePreview)>]
+    [<ResourceDisplayName(SRProperties.FSharpInteractivePreviewMode)>]
+    [<ResourceDescription(SRProperties.FSharpInteractivePreviewModeDescr)>]
+    member this.FsiPreview with get() = SessionsProperties.fsiPreview and set (x:bool) = SessionsProperties.fsiPreview <- x
+
 // CompletionSet
-type internal FsiCompletionSet(imageList,source:Source) = 
+type internal FsiCompletionSet(imageList,source:Source) =
     inherit CompletionSet(imageList, source)
 
 // Declarations

vsintegration/src/FSharp.VS.FSI/sessions.fs

@@ -70,6 +70,7 @@ module SessionsProperties =
     let mutable fsiArgs = "--optimize"
     let mutable fsiShadowCopy = true
     let mutable fsiDebugMode = false
+    let mutable fsiPreview = false
 
 // This code pre-dates the events/object system.
 // Later: Tidy up.
@@ -218,7 +219,7 @@ let fsiStartInfo channelName =
 
     let addBoolOption name value args = sprintf "%s --%s%s" args name (if value then "+" else "-")
     let addStringOption name value args = sprintf "%s --%s:%O" args name value
-    
+
     let procArgs =
         ""
         |> addStringOption "fsi-server-output-codepage" outCP
@@ -227,11 +228,18 @@ let fsiStartInfo channelName =
         |> addStringOption "fsi-server" channelName
         |> (fun s -> s +  sprintf " %s" SessionsProperties.fsiArgs)
         |> addBoolOption "shadowcopyreferences" SessionsProperties.fsiShadowCopy
-        |> (fun args -> if SessionsProperties.fsiDebugMode then
-                            // for best debug experience, need optimizations OFF and debug info ON
-                            // tack these on the the end, they will override whatever comes earlier
-                            args |> addBoolOption "optimize" false |> addBoolOption "debug" true
-                        else args)
+        |> (fun args ->
+            // for best debug experience, need optimizations OFF and debug info ON
+            // tack these on the the end, they will override whatever comes earlier
+            if SessionsProperties.fsiDebugMode then
+                args |> addBoolOption "optimize" false |> addBoolOption "debug" true
+            else
+                args)
+        |> (fun args ->
+            if SessionsProperties.fsiPreview then
+                args |> addStringOption "langversion" "preview"
+            else
+                args)
 
     procInfo.Arguments <- procArgs
     procInfo.CreateNoWindow <- true

vsintegration/src/FSharp.VS.FSI/xlf/Properties.cs.xlf

@@ -27,6 +27,21 @@
         <target state="translated">Různé</target>
         <note />
       </trans-unit>
+      <trans-unit id="FSharpInteractivePreview">
+        <source>FSI Preview</source>
+        <target state="new">FSI Preview</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="FSharpInteractivePreviewMode">
+        <source>Enable preview language features</source>
+        <target state="new">Enable preview language features</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="FSharpInteractivePreviewModeDescr">
+        <source>Enable preview of in-development language features in F# Interactive</source>
+        <target state="new">Enable preview of in-development language features in F# Interactive</target>
+        <note />
+      </trans-unit>
       <trans-unit id="FSharpInteractiveShadowCopy">
         <source>Shadow copy assemblies</source>
         <target state="translated">Sestavení stínových kopií</target>

vsintegration/src/FSharp.VS.FSI/xlf/Properties.de.xlf

@@ -27,6 +27,21 @@
         <target state="translated">Verschiedene</target>
         <note />
       </trans-unit>
+      <trans-unit id="FSharpInteractivePreview">
+        <source>FSI Preview</source>
+        <target state="new">FSI Preview</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="FSharpInteractivePreviewMode">
+        <source>Enable preview language features</source>
+        <target state="new">Enable preview language features</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="FSharpInteractivePreviewModeDescr">
+        <source>Enable preview of in-development language features in F# Interactive</source>
+        <target state="new">Enable preview of in-development language features in F# Interactive</target>
+        <note />
+      </trans-unit>
       <trans-unit id="FSharpInteractiveShadowCopy">
         <source>Shadow copy assemblies</source>
         <target state="translated">Schattenkopie-Assemblys</target>

vsintegration/src/FSharp.VS.FSI/xlf/Properties.es.xlf

@@ -27,6 +27,21 @@
         <target state="translated">Varios</target>
         <note />
       </trans-unit>
+      <trans-unit id="FSharpInteractivePreview">
+        <source>FSI Preview</source>
+        <target state="new">FSI Preview</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="FSharpInteractivePreviewMode">
+        <source>Enable preview language features</source>
+        <target state="new">Enable preview language features</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="FSharpInteractivePreviewModeDescr">
+        <source>Enable preview of in-development language features in F# Interactive</source>
+        <target state="new">Enable preview of in-development language features in F# Interactive</target>
+        <note />
+      </trans-unit>
       <trans-unit id="FSharpInteractiveShadowCopy">
         <source>Shadow copy assemblies</source>
         <target state="translated">Ensamblados de instantánea</target>

vsintegration/src/FSharp.VS.FSI/xlf/Properties.fr.xlf

@@ -27,6 +27,21 @@
         <target state="translated">Divers</target>
         <note />
       </trans-unit>
+      <trans-unit id="FSharpInteractivePreview">
+        <source>FSI Preview</source>
+        <target state="new">FSI Preview</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="FSharpInteractivePreviewMode">
+        <source>Enable preview language features</source>
+        <target state="new">Enable preview language features</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="FSharpInteractivePreviewModeDescr">
+        <source>Enable preview of in-development language features in F# Interactive</source>
+        <target state="new">Enable preview of in-development language features in F# Interactive</target>
+        <note />
+      </trans-unit>
       <trans-unit id="FSharpInteractiveShadowCopy">
         <source>Shadow copy assemblies</source>
         <target state="translated">Assemblys de cliché instantané</target>

vsintegration/src/FSharp.VS.FSI/xlf/Properties.it.xlf

@@ -27,6 +27,21 @@
         <target state="translated">Varie</target>
         <note />
       </trans-unit>
+      <trans-unit id="FSharpInteractivePreview">
+        <source>FSI Preview</source>
+        <target state="new">FSI Preview</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="FSharpInteractivePreviewMode">
+        <source>Enable preview language features</source>
+        <target state="new">Enable preview language features</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="FSharpInteractivePreviewModeDescr">
+        <source>Enable preview of in-development language features in F# Interactive</source>
+        <target state="new">Enable preview of in-development language features in F# Interactive</target>
+        <note />
+      </trans-unit>
       <trans-unit id="FSharpInteractiveShadowCopy">
         <source>Shadow copy assemblies</source>
         <target state="translated">Assembly copie shadow</target>

vsintegration/src/FSharp.VS.FSI/xlf/Properties.ja.xlf

@@ -27,6 +27,21 @@
         <target state="translated">その他</target>
         <note />
       </trans-unit>
+      <trans-unit id="FSharpInteractivePreview">
+        <source>FSI Preview</source>
+        <target state="new">FSI Preview</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="FSharpInteractivePreviewMode">
+        <source>Enable preview language features</source>
+        <target state="new">Enable preview language features</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="FSharpInteractivePreviewModeDescr">
+        <source>Enable preview of in-development language features in F# Interactive</source>
+        <target state="new">Enable preview of in-development language features in F# Interactive</target>
+        <note />
+      </trans-unit>
       <trans-unit id="FSharpInteractiveShadowCopy">
         <source>Shadow copy assemblies</source>
         <target state="translated">シャドウ コピーのアセンブリ</target>

vsintegration/src/FSharp.VS.FSI/xlf/Properties.ko.xlf

@@ -27,6 +27,21 @@
         <target state="translated">기타</target>
         <note />
       </trans-unit>
+      <trans-unit id="FSharpInteractivePreview">
+        <source>FSI Preview</source>
+        <target state="new">FSI Preview</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="FSharpInteractivePreviewMode">
+        <source>Enable preview language features</source>
+        <target state="new">Enable preview language features</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="FSharpInteractivePreviewModeDescr">
+        <source>Enable preview of in-development language features in F# Interactive</source>
+        <target state="new">Enable preview of in-development language features in F# Interactive</target>
+        <note />
+      </trans-unit>
       <trans-unit id="FSharpInteractiveShadowCopy">
         <source>Shadow copy assemblies</source>
         <target state="translated">섀도 복사본 어셈블리</target>

vsintegration/src/FSharp.VS.FSI/xlf/Properties.pl.xlf

@@ -27,6 +27,21 @@
         <target state="translated">Różne</target>
         <note />
       </trans-unit>
+      <trans-unit id="FSharpInteractivePreview">
+        <source>FSI Preview</source>
+        <target state="new">FSI Preview</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="FSharpInteractivePreviewMode">
+        <source>Enable preview language features</source>
+        <target state="new">Enable preview language features</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="FSharpInteractivePreviewModeDescr">
+        <source>Enable preview of in-development language features in F# Interactive</source>
+        <target state="new">Enable preview of in-development language features in F# Interactive</target>
+        <note />
+      </trans-unit>
       <trans-unit id="FSharpInteractiveShadowCopy">
         <source>Shadow copy assemblies</source>
         <target state="translated">Zestawy kopii w tle</target>